Manufacture of portland cement



To all whom it may concern.-

UNITED STATES PATENT OFFICE.

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ROBERT W. LESLEY, OF PHILADELPHIA, PENNSYLVANIA.

MANUFACTURE OF PORTLAND CEMENT.

SPECIFICATION forming part of Letters Patent No. 313,217, dated March 31885.

Application filed June 14, 1884. (No specimens.)

practical effectis as follows: I take cement- 5 Y rocks or hydrauliclimestones suitable for the manufacture of the ordinary homemade cemcut,and, after calcining them in the manner usually practiced for suchpurposes, I add to '60 them twenty-five per cent., by weight, of theblack chalk above described in a raw condition.

The addition may be made either before or after or during the operationof grinding the calcined materialto a powder.

Another way of carrying my invention into practice is as follows: I takePortland-cement 7 material, calcine it to a clinker in the manp nerusually practiced in that industry, and

then to the calcined product I add, either before, during, or after thegrinding operation,

thirty per cent. of black chalk in a raw condition. In some cases, wherethe cement material may be underlimed, I have found that the addition ofthe raw black chalk in so large Wm M b I aproportion may slightly weakenthestrength colmlfidjigl gnts by t e couminTitioiifiiit'IftlT ofthecement, and in such case I find the difcelnent mateniifliift'eicalcilfatioriaiid before culty can be overcome by the addi tlo n of mgthigrinil ingoperation, of slaked lime as covered by the invention of'25 a new material whereby" hedi'sadvantages David uriifiths, this dayfiled. above referred to are large y, if not entirely, I do not confinemyself to the exact proovercome and a black or dark-colored cemportionshereinbcfore stated, as the same may cut of greater strength and of lesscost than be varied, according to the darkness of color thosemanufactured undefithe processes now desired, without materiallydeparting from 30 in use can be produced. The material I use myinvention; nor do I desire to be underis found in various parts ofPennsylvania, stood as restricting myself to the methods of butprincipally in Lehigh county, where it using it hereinbefore described,but I desire is known as black chalk. It is a black to include all ofthe methods mentioned, as

, Be itknown that I, ROBERT IV. LEsLEY, of Philadelphia, State ofPennsylvania, have invented a certain new and useful Improve- 5 ment inthe Manufacture of Portland Cement,

of which the following is a specification.

In artificial stone-work cements of various colors are greatly soughtaft-er, and tiles and blocks of various colors and designs arelarge- 1oly used. Black and gray and slate-color are among the colors preferredfor these purposes, and in order to produce them, as well as other darkcolors, various materials-such as lampblack, powdered charcoal, &c.-havebeen [5 used, in most cases, however, with the efl'ect of materiallyweakening the strength of the cement by the addition of an inertmaterial, while at the same time materially adding to the cost ofitsproduction.

2. My invention relates to a newinvention for the purpose ofmakin' blackand other darkmineral having a gr'ea'sy textureand harden-s ing whenexposed to the air. 'Ghemically it contains varying proportions ofsilica, aluwell as any others; and

What I claim as new, and desire-Letters Patent for, '1smina, and lime,and a considerable proportion of iron. I have found that by taking thismaterial in its raw condition and com- 40 biningit in varyingproportions,according to the degree of darkness desired, with the cementmaterial of either Portland or homemade cements, after the calciningoperation, and during,.before, or after the grind- 5 ing operation,black or dark-colored cements can be produced of the greatest strengthand with the minimum of cost, as the material used is frequently to befound in proximity to cement deposits, and possesses itself, by 50 itschemical composition, cement-making elements which combineadvantageously with the cement material. Being, moreover, of aclayeycharacter, it is easily and economically ground. -55 One way of carryingmy invention into 1. The hereinbefore described improvement in themanufacture of hydraulic cement, which consists in incorporating withcalcined cement rocks or hydraulic limestones- 5 such as are used in themanufacture of hydraulic cements-black chalk, substantially in themanner and proportions set forth.

2. The hereinbefore described improvement in the manufacture of Portlandcement, which consists in incorporating with the cement material aftercalcination black chalk, substantially in the proportions and in themanner set forth.

In testimony whereof I have hereunto set my hand this 12th day of June,A. D. 1884.

R. IV. LESLEY.

Witnesses:

A. D. KACHLINE, OLIVER J. Fnawrz.

